This invention relates generally to multilayer papermaking fabrics. More particularly, this invention relates to techniques of forming a seam for joining the ends of a length of such flat woven fabric to form a continuous belt for use on a papermaking machine.
Early papermaking fabrics, whether used for forming or for drying were conventionally made of single layer weaves. More recently double, triple and other multilayer fabrics have become more popular because of their inherently superior qualities in wear, fluid permeability and the surface formed on resulting paper products. While such fabrics may be formed by an endless weaving technique in which the complete fabric belt is woven at one time, many of the more complex fabric weaves, and particularly those of multiple layers, are more conveniently woven flat, forming a strip of defined length whose ends are then joined by a suitable seaming technique to form an endless belt.
Traditional multilayer seaming techniques created the joins securing the opposed ends of each such machine direction filament at woven fabric knuckles, generally in the manner used traditionally in forming single layer fabric belts. In one known multilayer seaming technique the join securing the ends of each machine direction filament is formed on the sheet side of the belt. This is proven undesirable both in forming a large hole in the surface of the fabric and by the creation of pickets formed by the machine direction tails on the sheet side surface.
Prior art machine side joins have eliminated the pickets formed by the joined tails but have either created excessively long cross machine direction floats on the machine side surface or have created drainage path restrictions as a result of excess machine direction filament material in the join.